Today, there are numerous medical ailments and diseases which can be treated by medicines, such as drugs, hormones, etc. One such disease is diabetes mellitus which can be characterized by the absence of or inappropriate utilization of insulin secreted by the pancreas. Insulin acts to facilitate the delivery of glucose into the cells where it undergoes various biochemical reactions. The result of diabetes is high levels of glucose in the blood and low levels of cellular glucose which can be fatal.
Generally, there are two forms of diabetes. Type I diabetes usually emerges before the age of 30 and is characterized by a reduction in the amount of insulin secreted by the pancreas. Type II diabetes is far more common and usually starts after age 30 and is characterized by normal insulin secretion but the biochemical composition of the insulin does not facilitate the glucose transport effectively.
To ameliorate this problem, conventional treatment has included one to several subcutaneous injections of insulin per day. More recently, insulin is delivered to the patient on a continuous basal basis as well as a bolus basis by a portable infusion pump, such as disclosed in U.S. Pat. No. 4,498,843 to Schneider et al These pumps typically include a syringe or cartridge filled with insulin, an electromechanical mechanism that advances the syringe or cartridge plunger, and a controller that controls the proper dosage. Catheter tubing delivers the insulin from the syringe to an infusion tubing and needle set which is inserted under the skin of the patient.
Prior art systems for delivering an infusable liquid to a body have suffered from at least two deficiencies. First, these portable systems are very expensive. For example, the initial cost alone for the system and accessories can be between 4,000 and 6,000 dollars. Recurring costs of the system and dressings can average between 200 and 300 dollars per month. Second, the catheter tubing of these systems requires a substantial amount of insulin for priming purposes which can induce inaccuracies in the delivery dosage. Further, the tubing may easily kink resulting in a loss of delivery, or insufficient dosing of, the infusable to the patient.
Accordingly, there is a need for an inexpensive and hence disposable infusion device which accurately, consistently, and reliably delivers infusable liquids, such as insulin, to a patient. In accordance with the present invention, a disposable infusion device includes a housing which defines a bladder chamber. A compressible bladder is disposed in the bladder chamber and is compressed by the housing upon filling the bladder with an infusable liquid to create a pressurized bladder. The infusion device further includes a delivery system for subcutaneously delivering the infusable liquid to the body of the user.
In accordance with one aspect of the present invention, the delivery system includes a collapsible member that supports an injection needle and a cannula. The injection needle is used to insert the cannula into the skin of the body being treated. The cannula is in communication with the bladder during delivery of the infusable liquid. In one embodiment, the housing includes microfluidic passageways that allow communication between fluid in the bladder and the cannula.
The housing includes a first side and a second side with an adhesive or adherent on the first side for attaching the infusion device to the skin of the body for a period of time, such as 3-5 days. Preferably, the adhesive forms a seal around the cannula to create a sanitary injection site into the body.
In accordance with other aspects of the present invention, the infusion device includes an alarm or radio frequency signal to warn the user when the bladder is substantially or nearly empty. This alarm can include an audible or vibrational alarm. The infusion device can also include an occlusion alarm to warn the user when a predetermined amount of infusable liquid fails to be delivered to the body.
In accordance with yet other aspects of the present invention, the infusion device includes a controller, such as a microcontroller, for controlling operation of the infusion device. For example, the controller can assess, diagnose, or transmit information about and operation of the infusion device. A power source or battery is used to power the controller. The controller is programmable, in one embodiment, for injecting predetermined amounts of infusable liquid, preferably selected by a user input, into the body.
A remote control device can be used to program and control operation of the infusion device. A signaling mechanism, such as an LED, can be included on the infusion device to confirm programming by the remote control device. The remote control device can include a memory storage device to store the programmed instructions sent to the infusion device, and to provide history information on the performance/operations of the device.